During the 22nd Century, an alien race called the Gamilus Empire suddenly declared war on Earth. Mankind suffered repeated defeats again the technologically superior Gamilus empire. Mankind's domain within the solar system shrank with each passing year. The Jupiter defense line, the siege of Mars, the defense of the lunar orbit, and lastly, the final battle of Earth's defense. It was during the last battle that Gamilus unleashed a devastating nuclear attack against Earth and rendered most of Earth's surface too full of radioactive contamination for human habitation. Despite that, Earth was successfully defended. Mankind transformed Earth into a fortress and managed to survive. Gamilus firmly controlled space and mankind had no way of fighting back. The saving grace came in the form of a message from another alien race: "if you can travel 14800 light years to our planet Iscandar, then we can give a a device that can clean up all the radiation on earth." The message itself was hard to trust, but attached were the design plans for the Wave Motion Engine. After the theory behind Wave Motion Energy proved true, the message became quite trustworthy. And so mankind scraped up whatever meager productivity that was left and constructed twelve brand new Wave Motion Engine-equipped Space Battleships all over the world.